STATE OF FLORIDA 

 DEPARTMENT OF ENVIRONMENTAL PROTECTION 

David B. Struhs, Secretary 

DIVISION OF RESOURCE ASSESSMENT AND MANAGEMENT 

Edwin J. Conklin, Director 

FLORIDA GEOLOGICAL SURVEY 

Walter Schmidt, State Geologist and Chief 

OPEN-FILE REPORT 80 

TEXT TO ACCOMPANY THE 

GEOLOGIC MAP OF FLORIDA 

By 

Thomas M. Scott, P.G. #99

FLORIDA GEOLOGICAL SURVEY 

Tallahassee, Florida 

2001 

ISSN 1058-1391

FLORIDA GEOLOGICAL SURVEY 

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TEXT TO ACCOMPANY 

THE GEOLOGIC MAP OF FLORIDA

By 

Thomas M. Scott, P.G. 99 

INTRODUCTION 

 The Florida Platform lies on the south-central part of the North American Plate, 

extending to the southeast from the North American continent separating the Gulf of Mexico 

from the Atlantic Ocean. The Florida Platform, as measured above the 300 foot (91 meter) 

isobath, spans more than 350 miles (565 kilometers) at its greatest width and extends southward 

more than 450 miles (725 kilometers) at its greatest length. The modern Florida peninsula is the 

exposed part of the platform and lies predominantly east of the axis of the platform. Most of the 

State of Florida lies on the Florida Platform; the western panhandle is part of the Gulf Coastal 

Plain. 

 The basement rocks of the Florida Platform include Precambrian-Cambrian igneous 

rocks, Ordovician-Devonian sedimentary rocks, and Triassic-Jurassic volcanic rocks (Arthur, 

1988). Florida’s igneous and sedimentary foundation separated from what is now the African 

Plate when the super-continent Pangea rifted apart in the Triassic (pre-Middle Jurassic?) and 

sutured to the North American craton (Smith, 1982). 

 A thick sequence of mid-Jurassic to Holocene sediments (unlithified to well lithified) 

lies unconformably upon the eroded surface of the basement rocks. Carbonate sedimentation 

predominated from mid-Jurassic until at least mid-Oligocene on most of the Florida Platform. In 

response to renewed uplift and erosion in the Appalachian highlands to the north and sea-level 

fluctuations, siliciclastic sediments began to encroach upon the carbonate-depositing 

environments of the Florida Platform. Deposition of siliciclastic-bearing carbonates and 

siliciclastic sediments predominated from mid-Oligocene to the Holocene over much of the 

platform. Numerous disconformities that formed in response to nondeposition and erosion 

resulting from sea-level fluctuations occur within the stratigraphic section. 

 The oldest sediments exposed at the modern land surface are Middle Eocene carbonates 

of the Avon Park Formation which crop out on the crest of the Ocala Platform in west-central 

Florida. The pattern of exposures of younger sediments is obvious on the geologic map. Much 

of the state is blanketed by Pliocene to Holocene siliciclastic and siliciclastic-bearing sediments 

that were deposited in response to late Tertiary and Quaternary sea-level fluctuations. 

 The characteristic landscape of Florida is relatively to extremely flat. There are few 

large, natural exposures and limited smaller exposures that geologists can investigate. The result 

is that geologists must rely primarily on de-watered or dry pits and quarries for exposures and 

must make use of subsurface data in studying the geology of Florida. Subsurface data, in the 

form of well cuttings and cores, were utilized extensively in the development of this map. 

Formational tops recognized in the subsurface have been extrapolated to the surface where 

exposures are limited. 

PREVIOUS INVESTIGATIONS 

Previously published geological maps of Florida include Smith (1881), Dall and Harris 

(1892), Matson et al. (1909), Sellards, Gunter and Cooke (1922), Cooke and Mossom (1929), 

Cooke (1945), Vernon (1951), Vernon and Puri (1964) and Brooks (1982). 
OPEN FILE REPORT NO. 80 

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 Groundwork for a new geologic map of Florida began in the 1980s with a county-level 

mapping effort as part of a statewide radon investigation. The county maps created for the radon 

project were merged and modified to produce a new State map. The geologists from the Florida 

Geological Survey (FGS) involved in the project included Jon Arthur, Ken Campbell, Joel 

Duncan, Frank Rupert, and Tom Scott. Tom Missimer, Missimer International, Ft. Myers, 

Florida was part of the mapping team for Charlotte and Lee Counties. Previous mapping 

provided a basis for this project. Geologists involved in the preliminary mapping included 

Paulette Bond, Richard Johnson, Ed Lane, Walt Schmidt and Bill Yon. 

METHODS 

 Much of Florida is covered by a blanket of Pliocene to Holocene, undifferentiated 

siliciclastics that range in thickness from less than one foot to greater than 100 feet. As a result, 

in developing the criteria for producing this map, FGS geologists decided to map the first 

recognizable lithostratigraphic unit occurring within 20 feet (6.1 meters) of the land surface. In 

areas where highly karstic limestones underlie the undifferentiated siliciclastics, paleosinkholes 

may be infilled with significantly thicker sequences of siliciclastics. If the shallowest 

occurrences of the karstic carbonates were 20 feet (6.1 meters) or less below land surface, the 

carbonate lithostratigraphic unit was mapped. If the carbonates lie more than 20 feet (6.1 

meters) below land surface, an undifferentiated siliciclastic unit was mapped. 

 Undifferentiated siliciclastic sediments occur in significant thickness (>20 feet [6.1 

meters]) over much of the Gulf Coastal Lowlands (White, 1970; Scott, in preparation) and the 

eastern part of the Florida peninsula. Where these sediments were mapped, efforts were made to 

determine if beach-ridge or dune topography was present in order to subdivide the siliciclastic 

sediments. 

 Lithostratigraphic terminology applied in this mapping effort followed, with limited 

changes, the lithostratigraphic framework delineated for the Gulf Coast Region chart from the 

Correlation of Stratigraphic Units of North America Project (COSUNA) (Braunstein et al., 

1988). Although some of the units depicted on the COSUNA chart have a significant 

biostratigraphic basis, the COSUNA chart represents the best effort to date to provide an 

accurate stratigraphic framework for the Florida Platform and surrounding regions. 

 A peer review of the geologic map and this text by members of the geologic community 

outside the FGS was done by S. Upchurch, R. Portell, T. Missimer, J. Bryan, J. Vecchioli, A. 

Tihansky, K. Cunningham, G. L. Barr and R. Spechler. The FGS greatly appreciates the efforts 

of these geologists. 

 FGS cartographers Jim Jones and Ted Kiper worked on the initial phase of this project. 

CAD analyst Amy Graves assisted in the map preparation. Lou Cross and Peter Krafft from 

Florida Resources and Environmental Analysis Center, Florida State University, finalized the 

map in preparation for publication. 

STRATIGRAPHIC COLUMN AND CROSS SECTIONS

 Lithostratigraphic units expressed on the State geological map range from Middle Eocene 

to Holocene. The stratigraphic column showing the lithostratigraphic units utilized on the map 

delineates only the formations occurring at or near the surface (Figure 1). Table 1 lists the 

stratigraphic units and provides a brief lithologic components list. Cross sections (Figures 2 and 

3) were constructed utilizing cores and well cuttings from the FGS well cuttings and core 

repository. By necessity, the cross sections show some lithostratigraphic units that do not crop 
FLORIDA GEOLOGICAL SURVEY 

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out. These include the Pensacola Clay, Coarse Clastics, Bruce Creek Limestone, and the Long 

Key Formation. Table 2 lists information for the wells used in the cross sections. 

Table 1. Stratigraphic units and lithologies. 

Unit Lithologies

TERTIARY 

Middle Eocene 

Tap Avon Park Formation limestone, dolostone 

Upper Eocene 

To Ocala Limestone limestone, dolostone 

Lower Oligocene 

Ts Suwannee Limestone limestone 

Tsm Suwannee-Marianna Limestones Undif. limestone 

Upper Oligocene to Middle Miocene 

Tha Hawthorn Group, Arcadia Formation dolostone, limestone, sand, 

 clay, phosphate 

That Hawthorn Group, Tampa Member limestone, dolostone, sand, 

clay 

Miocene 

Tsmk St. Marks Formation limestone, sand 

Tch Chattahoochee Formation dolostone, limestone, sand, 

clay, 

Th Hawthorn Group dolostone, limestone, sand, 

clay, phosphate 

Tht Hawthorn Group, Torreya Formation clay, sand, limestone 

Ths Hawthorn Group, Statenville Formation dolostone, sand, clay, 

phosphate 

Thc Hawthorn Group, Coosawhatchie Formation sand, clay limestone, 

dolostone, phosphate 

Tab Alum Bluff Group clay, sand 

Miocene-Pliocene 

Thp Hawthorn Group, Peace River Formation sand, clay, dolostone, 

 phosphate 

Thpb Hawthorn Group, Peace River Formation, sand, clay, phosphate, 

Bone Valley Member dolostone 

Thcc Hawthorn Group, Coosawhatchie Formation, clay, sand, limestone 

 Charlton Member 
OPEN FILE REPORT NO. 80 

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TABLE 1 (CONTINUED) 

TERTIARY/QUATERNARY 

Unit Lithologies 

Pliocene 

Tt Tamiami Formation limestone, sand, clay 

Tjb Jackson Bluff Formation clay, sand 

Tic Intracoastal Formation limestone, sand, clay 

Tmc Miccosukee Formation sand, clay 

Tci Citronelle Formation sand, clay 

Tc Cypresshead Formation sand, clay 

TQuc Reworked Cypresshead Formation sand, clay 

TQd Dunes sand 

TQu Undifferentiated sediments sand, clay 

TQsu Shell-bearing sediments shells, sand, clay 

QUATERNARY 

Pleistocene 

Qtr Trail Ridge sands sand, heavy minerals 

Qm Miami Limestone limestone, sand 

Qk Key Largo Limestone limestone 

Qa Anastasia Formation limestone, coquina, sand 

Pleistocene/Holocene 

Qu Undifferentiated sand, clay, organics 

Qbd Beach Ridge and Dune sand 

Qal Alluvium sand, clay, organics 

Holocene 

Qh Holocene sediments sand, clay, organics 

 
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Table 2. Wells used in cross sections. 

 W # County Section Town 

ship 

Range Elevation 

(msl) 

Composite 

 with W# 

Cross Section

 & Well # 

 

148 Walton 12 1N 19W 200 7951 4 A-A' 

275 Lake se/se 17 24S 25E 113 5 B-B' 

935 Dade sw/sw 31 53S 35E 18 9 B-B' 

1345 Okaloosa sw/ne 1 3N 25W 189 3 A-A' 

1465 Alachua ne/se/sw 23 8S 18E 102 3 B-B' 

1482 Marion sw/nw 16 16S 23E 74 4 B-B' 

1596 Madison sw/se 6 1S 10E 107 15803 9 A-A' 

1610 Calhoun nw/se 31 2N 9W 217 11270 6 A-A' 

1754 Polk sw/sw 18 30S 28E 147 6 B-B' 

1758 Washington sw/sw 31 2N 13W 125 10954 5 A-A' 

1768 Gadsden ne/nw 35 2N 3W 200 15795 7 A-A' 

1789 Columbia se 22 1N 17E 129 1 B-B' 

1832 Columbia ne/ne 24 2S 16E 138 15162 10 A-A' 2 B-B'

1854 Jefferson 1 2S 3E 51 6931 8 A-A' 

3455 Santa Rosa ne/ne 10 2N 27W 35 2 A-A' 

4597 Escambia nw/nw 2 1N 31W 110 1 A-A' 

6931 Jefferson se/ne 29 1S 4E 200 1854 8 A-A' 

7971 Walton se/sw 9 1N 18W 195 148 4 A-A' 

8736 Duval ne/ne 23 1S 24E 82 8881 11 A-A' 

8881 Duval ne/ne 23 1S 24E 81 8736 11 A-A' 

10954 Washington ne 16 1N 14W 125 1758 5 A-A' 

11270 Calhoun nw/ne 13 1N 10W 125 1610 6 A-A' 

15162 Columbia se/sw 23 2S 17E 140 1832 2 B-B' 

15644 Highlands 17 37S 30E 104 7 B-B' 

15795 Gadsden ne/ne 6 1N 2W 200 1768 7 A-A' 

15803 Madison ne/se 34 1N 9E 161 1596 9 A-A' 

16058 Hendry se/sw 27 45S 34E 18 8 B-B' 

17156 Monroe sw 26 64S 35E 1 11 B-B' 

17273 Dade sw 36 58S 36E 5 10 B-B' 

ODAW#1 Duval 4 2S 29E 15 12 A-A' 
OPEN FILE REPORT NO. 80 

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Figure 1. Stratigraphic column showing the lithostratigraphic units used on the map.
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Figure 2. Geological cross section locations.
OPEN FILE REPORT NO. 80 

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Figure 3. Geologic cross sections. 
FLORIDA GEOLOGICAL SURVEY 

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Figure 4. Geologic structures in Florida (modified from Scott, 1988). 
OPEN FILE REPORT NO. 80 

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GEOLOGIC STRUCTURES 

 The geologic structures (Figure 4) that have affected shallow Tertiary and Quaternary 

sediments of the Florida Platform have been defined by numerous authors (Puri and Vernon, 

1964; Miller, 1986; Scott, 1988; Scott, 1991). The majority of the structures recognized as 

influencing the deposition, erosion and alteration of the Cenozoic sediments in Florida do not 

appear to have had a significant effect on the surface expression of the lithostratigraphic units. 

These geologic structures include the Gulf Basin, Jacksonville Basin, St. Johns Platform, 

Sanford High, Brevard Platform, Osceola Low and the Okeechobee Basin (Scott, 1992). Those 

structural features that exerted an influence on the surficial or very near surface distribution of 

the Cenozoic sediments, or mark areas of significant facies changes, include the Gulf 

Trough/Apalachicola Embayment, Chattahoochee “Anticline” and the Ocala Platform. Eocene 

sediments crop out on the Chattahoochee Anticline and the Ocala Platform. The Gulf Trough/ 

Apalachicola Embayment formed an important bathymetric and environmental barrier from the 

latest Eocene or earliest Oligocene into the Miocene. As a result, the Oligocene carbonate facies 

east and south of the Gulf Trough/Apalachicola Embayment are distinctly different from those 

occurring to the west and north (see Schmidt [1984] and Bryan [1991] for discussion). 

LITHOSTRATIGRAPHIC UNITS 

TERTIARY SYSTEM 

Eocene Series 

Middle Eocene - Bartonian Stage 

Tap - Avon Park Formation - Middle Eocene carbonate sediments of peninsular Florida, 

as originally described by Applin and Applin (1944), were subdivided, in ascending order, into 

the Lake City Limestone and the Avon Park Limestone. Miller (1986) recommended combining 

the Lake City Limestone with the Avon Park Limestone and, due to the common occurrence of 

dolostone, referred to the unit as the Avon Park Formation. Carbonates of the Avon Park 

Formation are the oldest sediments exposed in the state. The Avon Park Formation crops out in 

a limited area in west-central peninsular Florida in Levy and Citrus Counties on the crest of the 

Ocala Platform. 

 The Avon Park Formation consists of cream to light-brown or tan, poorly indurated to 

well indurated, variably fossiliferous, limestone (grainstone, packstone and wackestone, with 

rare mudstone). These limestones are interbedded with tan to brown, very poorly indurated to 

well indurated, very fine to medium crystalline, fossiliferous (molds and casts), vuggy 

dolostones. The fossils present include mollusks, foraminifers, echinoids, algae and carbonized 

plant remains. Molds and casts of gypsum crystals occur locally. 

 The Avon Park Formation is part of the Floridan aquifer system (FAS). Parts of the 

Avon Park Formation comprise important, subregional confining units within the FAS (Miller, 

1986). 
FLORIDA GEOLOGICAL SURVEY 

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Upper Eocene - Priabonian Stage 

To - Ocala Limestone - Dall and Harris (1892) referred to the limestones exposed near 

Ocala, Marion County, in central peninsular Florida as the Ocala Limestone. Puri (1953, 1957) 

elevated the Ocala Limestone to group status recognizing its component formations on the basis 

of foraminiferal faunas (biozones). Scott (1991) reduced the Ocala Group to formational status 

in accordance with the North American Stratigraphic Code (North American Commission on 

Stratigraphic Nomenclature, 1983). 

 The Ocala Limestone consists of nearly pure limestones and occasional dolostones. It 

can be subdivided into lower and upper facies on the basis of lithology. The lower member is 

composed of a white to cream-colored, fine to medium grained, poorly to moderately indurated, 

very fossiliferous limestone (grainstone and packstone). The lower facies may not be present 

throughout the areal extent of the Ocala Limestone and may be partially to completely 

dolomitized in some regions (Miller, 1986). The upper facies is a white, poorly to well 

indurated, poorly sorted, very fossiliferous limestone (grainstone, packstone and wackestone). 

Silicified limestone (chert) is common in the upper facies. Fossils present in the Ocala 

Limestone include abundant large and smaller foraminifers, echinoids, bryozoans and mollusks. 

The large foraminifera Lepidocyclina sp. is abundant in the upper facies and extremely limited in 

the lower facies. The presence of these large foraminifers in the upper facies is quite distinctive. 

 The Ocala Limestone is at or near the surface within the Ocala Karst District in the westcentral to northwestern peninsula and within the Dougherty Plain District in the north-central 

panhandle (Scott, in preparation). In these areas, the Ocala Limestone exhibits extensive 

karstification. These karst features often have tens of feet (meters) of relief, dramatically 

influencing the topography of the Ocala Karst District and the Dougherty Plain District (Scott, in 

preparation). Numerous disappearing streams and springs occur within these areas. 

 The permeable, highly transmissive carbonates of the Ocala Limestone form an important 

part of the FAS. It is one of the most permeable rock units in the FAS (Miller, 1986). 

Tre - Residuum on Eocene sediments - The post-Eocene residuum lying on Eocene 

sediments in the panhandle consists of reddish brown, sandy clays and clayey sands with 

inclusions of weathered Eocene limestones. Some of the inclusions are silicified carbonates. 

Oligocene Series 

Lower Oligocene - Rupelian Stage 

 Previous geologic maps of Florida presented the Lower Oligocene sediments exposed at 

the surface or in the shallow subsurface in a variety of ways. Cooke (1945) mapped, in 

ascending order, the Marianna Limestone, Byram Formation, Suwannee Limestone and the Flint 

River Formation. Vernon and Puri (1964) identified the Marianna Limestone, “Byram” 

Formation, Duncan Church beds and the Suwannee Limestone. Brooks (1982) recognized the 

Marianna Limestone, Suwannee Limestone and the Duncan Church facies of the Suwannee 

Limestone. The variations in the stratigraphic units are indicative of the confusion over the 

lithologic recognition and subdivision of the Lower Oligocene sediments. The confusion is at 

least partially due to the use of biostratigraphic data to subdivide the lithostratigraphic units. 
OPEN FILE REPORT NO. 80 

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 Huddlestun (1993) recognized a tripartite subdivision in the type area of the Suwannee 

Limestone in northwestern peninsular Florida and proposed the Ellaville Limestone, 

Suwannacoochee Dolostone and Suwannee Limestone. In the panhandle, west of the Gulf 

Trough, Huddlestun (1993) recognized the Marianna Limestone and an undifferentiated 

residuum as the Oligocene sediments extending into Florida’s panhandle from Georgia. 

Huddlestun (1993) also recognized Bucatunna Formation, Florala Limestone, Bridgeboro 

Limestone and an unnamed marl in Okaloosa and Walton Counties. 

 Bryan (1991, 1993) provides a better framework for the recognition of the various facies 

within the Lower Oligocene sediments. Within this framework, the Ellaville Limestone, 

Suwannacoochee Dolostone and Suwannee Limestone occur within his Florida Platform 

Association east and south of the Gulf Trough. West of the Gulf Trough in the Florida 

panhandle (Bryan’s Eastern Gulf Shelf Association), Bryan (1991) recognized the Bumpnose 

Limestone, Marianna Limestone, Bridgeboro Limestone, Florala Limestone, Suwannee 

Limestone, Byram Marl and Bucatunna Formation. 

 The limited data available, the occurrence of thin beds of some of these units and the 

questionable occurrence of other units made mapping the Lower Oligocene sediments in the 

central panhandle problematic. The approach selected by FGS geologists was to combine the 

units into several mappable units appropriate for the scale of the present map. These mappable 

units include: undifferentiated Oligocene sediments composed of the Bumpnose Limestone, 

Marianna Limestone, Bridgeboro Limestone, Florala Limestone, Suwannee Limestone, thin beds 

of the Byram Marl and Bucatunna Formation and undifferentiated Oligocene residuum (see 

Huddlestun [1993] for a discussion of the origin of the residuum). 

 The Lower Oligocene sediments of peninsular Florida are mapped as the Suwannee 

Limestone and are not subdivided into the Ellaville Limestone, Suwannacoochee Dolostone and 

Suwannee Limestone. This mapping convention was adopted by FGS geologists due to the 

limited data on the areal distribution of the Ellaville Limestone and Suwannacoochee Dolostone. 

Ts - Suwannee Limestone - Peninsular Lower Oligocene carbonates crop out on the 

northwestern, northeastern and southwestern flanks of the Ocala Platform. The Suwannee 

Limestone is absent from the eastern side of the Ocala Platform due to erosion, nondeposition or 

both, an area referred to as Orange Island (Bryan, 1991). 

 The Suwannee Limestone, originally named by Cooke and Mansfield (1936), consists of 

a white to cream, poorly to well indurated, fossiliferous, vuggy to moldic limestone (grainstone 

and packstone). The dolomitized parts of the Suwannee Limestone are gray, tan, light brown to 

moderate brown, moderately to well indurated, finely to coarsely crystalline, dolostone with 

limited occurrences of fossiliferous (molds and casts) beds. Silicified limestone is common in 

Suwannee Limestone. Fossils present in the Suwannee Limestone include mollusks, 

foraminifers, corals and echinoids. 

Tsm - Undifferentiated Lower Oligocene Sediments - The undifferentiated Lower 

Oligocene sediments of the central panhandle consist of white to cream-colored, poorly to well 

indurated, variably fossiliferous limestones (grainstone, packstone, wackestone and mudstone). 

Glauconite occurs in some sediments. Siliciclastics form a minor component in some sediments. 

Thin beds of siliciclastics (Byram Marl and Buccatuna Formation) are included in the 
FLORIDA GEOLOGICAL SURVEY 

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undifferentiated Lower Oligocene sediments. The Lower Oligocene carbonates form important 

parts of the upper FAS (Miller, 1986). 

Tro - Residuum on Oligocene sediments - The undifferentiated Oligocene residuum, 

mapped on parts of the Chattahoochee “Anticline”, characteristically consists of reddish brown, 

variably sandy clay with inclusions of variably fossiliferous, silicified limestone (Huddlestun, 

1993). The residuum includes Lower and Upper Oligocene weathered sediments (Huddlestun, 

1993). 

Oligocene - Miocene Series 

Upper Oligocene - Middle Miocene - Chattian - Serravalian Stage 

PENINSULA 

Lower Hawthorn Group 

 Recent investigations into the Oligocene of southern Florida documented the existence of 

a thick (>330 feet [100 meters]) Upper Oligocene section previously considered Miocene (Scott 

et al., 1994; Missimer and Scott, 1995; Brewster-Wingard et al., 1997). The Arcadia Formation, 

Hawthorn Group, previously thought to be predominantly Early Miocene (Scott, 1988), is now 

known to be late Early Oligocene to Middle Miocene (Brewster-Wingard et al., 1997; Missimer, 

1997). The Tampa Limestone (or Formation of previous usage [Puri and Vernon, 1964]) is a 

member of the Arcadia Formation, Hawthorn Group (Scott, 1988). The Tampa Member’s 

previous age assignment was latest Oligocene to Early Miocene (Scott, 1988). BrewsterWingard et al. (1997) recognized the Tampa Member as being Late Oligocene to Early Miocene. 

Tha - Hawthorn Group, Arcadia Formation - The undifferentiated Arcadia Formation 

and the Tampa Member crop out on the southwestern flank of the Ocala Platform from Pasco 

County southward to Sarasota County. Although ages of the outcropping sediments have not 

been accurately determined, stratigraphic position suggests that the Upper Oligocene parts of the 

Arcadia Formation and Tampa Member are exposed in this region, particularly from 

Hillsborough County northward to Pasco County. 

 The Arcadia Formation, named by Scott (1988), is predominantly a carbonate unit with a 

variable siliciclastic component, including thin beds of siliciclastics. Within the outcrop area, 

the Arcadia Formation, with the exception of the Tampa Member, is composed of yellowish gray 

to light olive gray to light brown, micro to finely crystalline, variably sandy, clayey, and 

phosphatic, fossiliferous limestones and dolostones. Thin beds of sand and clay are common. 

The sands are yellowish gray, very fine to medium grained, poorly to moderately indurated, 

clayey, dolomitic and phosphatic. The clays are yellowish gray to light olive gray, poorly to 

moderately indurated, sandy, silty, phosphatic and dolomitic. Molds and casts of mollusks are 

common in the dolostones. Silicified carbonates and opalized claystone are found in the Arcadia 

Formation. 

That - Arcadia Formation, Tampa Member - The Tampa Member consists predominantly 

of limestone with subordinate dolostone, sand and clay (Scott, 1988). The lithology of the 

Tampa Member is very similar to that of the subsurface limestone part of the Arcadia Formation 
OPEN FILE REPORT NO. 80 

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except that the Tampa Member contains noticeably less phosphate (Scott, 1988). The limestone 

in the Tampa is white to yellowish gray, fossiliferous and variably sandy and clayey mudstone, 

wackestone and packstone with minor to no phosphate grains. Sand and clay beds are like those 

in the undifferentiated Arcadia Formation. Mollusks and corals are common in the Tampa 

Member as molds and casts, silicified pseudomorphs and original shell material. The Tampa 

Member and the lower part of the Arcadia Formation form the upper part of the Floridan aquifer 

system (FAS) in parts of southern Florida (Miller, 1986; Scott, 1991). 

PANHANDLE 

 Upper Oligocene sediments are not known to crop out in the Florida panhandle. The 

Chickasawhay Formation of Alabama has been traced in the subsurface into the central 

panhandle but is not exposed on the Chattahoochee Anticline (Miller, 1986). 

Miocene Series 

Lower Miocene to Upper Miocene - Aquitanian to Messinian Stage 

 Sediments of the Miocene Series have been the focus of numerous investigations due to 

their complex nature and widespread occurrence in Florida (see Schmidt and Clark [1980], 

Huddlestun [1988] and Scott [1988] for a review of previous investigations). The Miocene 

sediments consist of siliciclastics, carbonates and mixed siliciclastic-carbonate lithologies with 

numerous lateral and vertical facies changes. Exposures are limited and most investigations 

dealt with these sediments in the subsurface. 

 Miocene sediments crop out or occur in the shallow subsurface on the northwestern flank 

of the Ocala Platform in the eastern panhandle to the flanks of the Chattahoochee “Anticline” in 

the central panhandle then into the western panhandle to Okaloosa County. In the peninsula, the 

Miocene sediments crop out or are in the shallow subsurface from the northern flank of the 

Ocala Platform in Hamilton, Columbia and Baker Counties southward to Charlotte County. 

Some of the most beautiful landscapes in the State occur where the Miocene sediments are 

exposed, eroded and often affected by karstification of underlying Paleogene carbonates. 

 The importance of the Miocene sediments in Florida is twofold - first, these sediments 

contain valuable mineral resources, primarily phosphate and adsorptive clays; and, second, the 

Miocene sediments comprise the intermediate confining unit and aquifer system. Whereas the 

principle geological hazard associated with Paleogene carbonates is karst development, the 

hazards associated with the Miocene sediments are radon gas and swelling clays. 

 Significant changes in age determinations or interpretations have occurred for the 

sediments traditionally considered as Miocene in the peninsula. Puri and Vernon (1964) 

recognized a simple three-fold subdivision of the Miocene in peninsular Florida. Their 

subdivision of the Miocene was that all Lower Miocene sediments were St. Marks Formation 

(Tampa [Note that they used Tampa as a stage name so all sediments that had been called Tampa 

were placed in the St. Marks Formation statewide]), Middle Miocene sediments were Hawthorn 

Formation and Upper Miocene sediments were Tamiami Formation. Poag (1972) placed the 

lower portion of the Chattahochee Formation in the Upper Oligocene. Currently, geologists 

recognize that the Hawthorn Group spans from the mid-Oligocene to Early Pliocene (Brewster-
FLORIDA GEOLOGICAL SURVEY 

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Wingard et al., 1997; Missimer, 1997). The Tamiami Formation is Early to Late Pliocene 

(Missimer, 1997). 

 The Miocene lithostratigraphic units recognized by this study in the panhandle include 

the Chattahoochee Formation, St. Marks Formation, Alum Bluff Group, Torreya Formation 

(Hawthorn Group) and residuum. In the peninsula, the Miocene units mapped include the 

undifferentiated Hawthorn Group, Coosawhatchie Formation, Charlton Member, and the Peace 

River Formation and its Bone Valley Member. 

Tch - Chattahoochee Formation - The Chattahoochee Formation, originally named by 

Dall and Stanley-Brown (1894), is predominantly a yellowish gray, poorly to moderately 

indurated, fine-grained, often fossiliferous (molds and casts), silty to finely sandy dolostone 

(Huddlestun, 1988). Siliciclastic beds and limestones may be present. 

 The Chattahoochee Formation is exposed in Jackson County, central panhandle, on the 

Chattahoochee “Anticline”. It grades laterally across the Gulf Trough into the St. Marks 

Formation through a broad transition area (Scott, 1986). The Chattahoochee Formation forms 

the upper part of the FAS in the central panhandle. 

Tsmk - St. Marks Formation - The Lower Miocene St. Marks Formation, named by 

Finch (1823), is exposed in Wakulla, Leon and Jefferson Counties on the northwestern flank of 

the Ocala Platform. It is a white to yellowish gray, poorly to moderately indurated, sandy, 

fossiliferous (molds and casts) limestone (packstone to wackestone). Mollusk molds and casts 

are often abundant. The St. Marks Formation makes up the upper part of the FAS in part of the 

eastern panhandle. 

Hawthorn Group 

The Hawthorn Group in Florida is composed of a number of different formations and 

members (Scott, 1988; Huddlestun, 1988). Most of the formations are defined from subsurface 

evaluations. As a result, for mapping purposes, all the component formations are not recognized 

on the geologic map. 

 In the eastern panhandle, the upper Lower Miocene Torreya Formation, including the 

Dogtown and Sopchoppy Members (Huddlestun and Hunter, 1982), comprises the entire 

Hawthorn Group (Scott, 1988). The Dogtown and Sopchoppy Members are not delineated on 

the map. 

 In northern peninsular Florida, the Hawthorn Group consists of the lower Lower Miocene 

Penney Farms Formation and, rarely, the Parachucla Formation; the upper Lower Miocene 

Marks Head Formation; the Middle Miocene Coosawhatchie Formation and the Statenville 

Formation (Scott, 1988; Huddlestun, 1988). The Charlton Member of the Coosawhatchie 

Formation is recognized in a limited area. The Penney Farms and Marks Head Formations are 

not recognized cropping out in significant exposures. The undifferentiated Hawthorn Group was 

mapped where component formations were questionable or difficult to differentiate due to very 

limited data. 

 In southern peninsular Florida, the Hawthorn Group formations include the Upper 

Oligocene to Middle Miocene Arcadia Formation including the Tampa and Nocatee Members 

and the Middle Miocene to Early Pliocene Peace River Formation with its Bone Valley Member 

and Wabasso beds (Scott, 1988). The Nocatee Member of the Arcadia Formation and the 
OPEN FILE REPORT NO. 80 

16 

Wabasso beds of the Peace River Formation were not recognized at or near land surface and do 

not appear on the geologic map. 

Tht - Torreya Formation - The Torreya Formation is exposed or near the surface from 

western Gadsden County eastward to western-most Hamilton County. It is informally 

subdivided into a lower carbonate unit and an upper siliciclastic unit (Scott, 1988). The majority 

of Torreya Formation outcrops expose the siliciclastic part of the unit. The carbonate sediments 

are white to light olive gray, generally poorly indurated, variably sandy and clayey, fossiliferous 

(molds and casts) limestone (mudstone and wackestone). The limestones often grade into 

calcareous-cemented sands. Phosphate is present in the carbonate sediments, particularly in the 

Sopchoppy Member. The siliciclastics vary from white to light olive gray, unconsolidated to 

poorly indurated, slightly clayey sands with minor phosphate to light gray to bluish gray, poorly 

consolidated, variably silty clay (Dogtown Member). The siliciclastics are sporadically 

fossiliferous. The Torreya Formation overlies the FAS and forms part of the intermediate 

confining unit/aquifer system. 

Thc - Coosawhatchie Formation - The Coosawhatchie Formation is exposed or lies 

beneath a thin overburden on the eastern flank of the Ocala Platform from southern Columbia 

County to southern Marion County. Within the outcrop region, the Coosawhatchie Formation 

varies from a light gray to olive gray, poorly consolidated, variably clayey and phosphatic sand 

with few fossils, to an olive gray, poorly to moderately consolidated, slightly sandy, silty clay 

with few to no fossils. Occasionally the sands will contain a dolomitic component and, rarely, 

the dominant lithology will be dolostone or limestone. Silicified nodules are often present in the 

Coosawhatchie Formation sediments in the outcrop region. The sediment may contain 20 

percent or more phosphate (Scott, 1988). Permeability of the Coosawhatchie sediments is 

generally low, forming part of the intermediate confining unit/aquifer system. 

Thcc - Coosawhatchie Formation, Charlton Member - The Charlton Member (originally 

the Charlton formation, Veatch and Stevenson, 1911), crops out only in northern Nassau County 

near and along the St. Marys River. The Charlton Member in this area consists primarily of light 

gray to greenish gray, poorly to moderately consolidated, dolomitic to calcareous, silty, sandy, 

locally fossiliferous clays. Few carbonate beds occur. 

Ths - Statenville Formation - The Statenville Formation occurs at or near the surface in a 

limited area of Hamilton, Columbia and Baker Counties on the northeastern flank of the Ocala 

Platform. The formation consists of interbedded sands, clays and dolostones with common to 

very abundant phosphate grains. The sands predominate and are light gray to light olive gray, 

poorly indurated, phosphatic, fine to coarse grained with scattered gravel and with minor 

occurrences of fossils. Clays are yellowish gray to olive gray, poorly consolidated, variably 

sandy and phosphatic, and variably dolomitic. The dolostones, which occur as thin beds, are 

yellowish gray to light orange, poorly to well indurated, sandy, clayey and phosphatic with 

scattered mollusk molds and casts. Phosphate occurs in the Statenville Formation in 

economically important amounts. Silicified fossils and opalized claystones are found in the 

Statenville Formation. Permeability of these sediments is generally low, forming part of the 

intermediate confining unit/aquifer system. 
FLORIDA GEOLOGICAL SURVEY 

17 

Th - Undifferentiated Hawthorn Group - The undifferentiated Hawthorn Group occurs at 

or near the surface near the southern flank of the Ocala Platform from Gilchrist County 

southward to Pasco County with isolated occurrences in Pinellas County. Correlation of these 

sediments to the formations of the Hawthorn Group exposed to the east and in the subsurface is 

uncertain. There is little to no phosphate present in these sediments and fossils are rare. Ages 

have not been documented but stratigraphic position suggests inclusion in the Hawthorn Group. 

These sediments may be residual from the weathering and erosion of the Hawthorn Group. The 

Hawthorn Group sediments on the Brooksville Ridge are deeply weathered and in some outcrops 

look like Cypresshead Formation siliciclastics. 

 The undifferentiated Hawthorn Group sediments are light olive gray and blue gray in 

unweathered sections to reddish brown in deeply weathered sections, poorly to moderately 

consolidated, clayey sands to silty clays and relatively pure clays. These sediments are part of 

the intermediate confining unit/aquifer system and provide an effective aquitard for the FAS, 

except where perforated by karst features. 

 Hard-rock phosphate deposits are associated with the undifferentiated Hawthorn Group 

sediments on the eastern flank of the Brooksville Ridge. The hard rock phosphate deposits were 

formed by the dissolution of phosphate in the Hawthorn sediments and redeposition in karst 

features. 

Tab - Alum Bluff Group - West of the Apalachicola River, the Hawthorn Group is 

replaced by the Alum Bluff Group. The Alum Bluff Group includes the Chipola Formation, Oak 

Grove Sand, Shoal River Formation, Choctawhatchee Formation and the Jackson Bluff 

Formation (Huddlestun, 1984; Braunstein et al., 1988). The formations included in this group 

are generally defined on the basis of their molluscan faunas and stratigraphic position (Schmidt 

and Clark, 1980). Puri (1953) described sediment facies as they relate to the formations of the 

Alum Bluff Group These sediments are lithologically distinct as a group, not as individual 

units. Brooks (1982) mapped much of the Alum Bluff Group as the Shoal River Formation. The 

Alum Bluff Group crops out or is beneath a thin overburden in the western panhandle from river 

valleys in Okaloosa County eastward to western Jackson County. 

 The Alum Bluff Group consists of clays, sands and shell beds which may vary from 

fossiliferous, sandy clays to unfossiliferous sands and clays and occasional carbonate beds 

(Huddlestun, 1984). Mica is a common constituent and glauconite and phosphate occur 

sporadically. Induration varies from essentially nonindurated in sands to well indurated in 

carbonate lenses. Colors range from cream to olive gray with mottled reddish brown in 

weathered sections. Sand grain size varies from very fine to very coarse with sporadic 

occurrences of gravel. These sediments generally have low permeabilities and are part of the 

intermediate confining unit/aquifer system. 

 

Trm - Residuum on Miocene sediments - The undifferentiated Miocene residuum, 

mapped on parts of the Chattahoochee “Anticline”, characteristically consists of reddish brown, 

variably sandy clay with inclusions of variably fossiliferous, silicified limestone. The residuum 

includes Lower to Upper Miocene and younger weathered sediments. 

Miocene - Pliocene Series 
OPEN FILE REPORT NO. 80 

18 

Middle Miocene-Lower Pliocene, Serravalian - Zanclean Stage 

Thp - Peace River Formation - The Peace River Formation crops out or is beneath a thin 

overburden on the southern part of the Ocala Platform extending into the Okeechobee Basin. 

These sediments were mapped from Hillsborough County southward to Charlotte County. 

Within this area, the Peace River Formation is composed of interbedded sands, clays and 

carbonates. The sands are generally light gray to olive gray, poorly consolidated, clayey, 

variably dolomitic, very fine to medium grained and phosphatic. The clays are yellowish gray to 

olive gray, poorly to moderately consolidated, sandy, silty, phosphatic and dolomitic. The 

carbonates are usually dolostone in the outcrop area. The dolostones are light gray to yellowish 

gray, poorly to well indurated, variably sandy and clayey, and phosphatic. Opaline chert is often 

found in these sediments. The phosphate content of the Peace River Formation sands is 

frequently high enough to be economically mined. Fossil mollusks occur as reworked casts, 

molds, and limited original shell material. Silicified corals and wood, and vertebrate fossils are 

also present. The Peace River Formation is widespread in southern Florida. It is part of the 

intermediate confining unit/aquifer system. 

Thpb - Bone Valley Member, Peace River Formation - The Bone Valley Member 

(originally the Bone Valley Formation of Matson and Clapp, 1909), Peace River Formation 

occurs in a limited area on the southern part of the Ocala Platform in Hillsborough, Polk and 

Hardee Counties. Throughout its extent, the Bone Valley Member is a clastic unit consisting of 

sand-sized and larger phosphate grains in a matrix of quartz sand, silt and clay. The lithology is 

highly variable, ranging from sandy, silty, phosphatic clays and relatively pure clays to clayey, 

phosphatic sands to sandy, clayey phosphorites (Webb and Crissinger, 1983). In general, 

consolidation is poor and colors range from white, light brown and yellowish gray to olive gray 

and blue green. Mollusks are found as reworked, often phosphatized casts. Vertebrate fossils 

occur in many of the beds within the Bone Valley Member. Shark’s teeth are often abundant. 

Silicified corals and wood are occasionally present as well. 

 The Bone Valley Member is an extremely important, unique phosphate deposit and has 

provided much of the phosphate production in the United States during the twentieth century. 

Mining of phosphate in the outcrop area began in 1888 (Cathcart, 1985) and continues to the 

present. 

Pliocene Series 

Lower Pliocene to Upper Pliocene - Zanclean to Piacenzian Stage 

 Florida’s Pliocene sediments have been the focus of numerous, primarily paleontologic, 

investigations due to abundant and diverse molluscan faunas. Although the majority of the 

Pliocene sediments are unfossiliferous siliciclastics, well preserved shell beds in southern 

Florida have attracted much attention (see papers in Scott and Allmon [1992]; Zullo et al.[1993]; 

Missimer [1997]). Despite the attention to these units, the lithostratigraphy of the Pliocene units 

remains poorly understood. 

 Pliocene sediments are distributed widely in Florida. In the panhandle and northern twothirds of the peninsula the Pliocene sediments are predominantly unfossiliferous siliciclastics. In 

the southern one-third of the peninsula, the Pliocene sediments are often fossiliferous 
FLORIDA GEOLOGICAL SURVEY 

19 

siliciclastics with carbonates becoming more abundant in southwestern Florida. The facies 

relationships within the marine Pliocene sediments of southern Florida are quite complex. 

Tt - Tamiami Formation - The Tamiami Formation (Mansfield, 1939) is a poorly defined 

lithostratigraphic unit containing a wide range of mixed carbonate-siliciclastic lithologies and 

associated faunas (Missimer, 1992). It occurs at or near the land surface in Charlotte, Lee, 

Hendry, Collier and Monroe Counties in the southern peninsula. A number of named and 

unnamed members are recognized within the Tamiami Formation. These include: the 

Buckingham Limestone Member; an unnamed tan clay and sand; an oyster (Hyotissa) facies, a 

sand facies, the Ochopee Limestone Member, the Bonita Springs Marl Member; an unnamed 

limestone facies; the Golden Gate Reef Member; and the Pinecrest Sand Member (Missimer, 

1992). The individual members of the Tamiami Formation were not separately mapped on the 

geological map. 

 Lithologies of the Tamiami Formation in the mapped area include: 1) light gray to tan, 

unconsolidated, fine to coarse grained, fossiliferous sand; 2) light gray to green, poorly 

consolidated, fossiliferous sandy clay to clayey sand; 3) light gray, poorly consolidated, very fine 

to medium grained, calcareous, fossiliferous sand; 4) white to light gray, poorly consolidated, 

sandy, fossiliferous limestone; and 5) white to light gray, moderately to well indurated, sandy, 

fossiliferous limestone. Phosphate is present in virtually all lithologies as limited quantities of 

sand- to gravel-sized grains. Fossils present in the Tamiami occur as molds, casts and original 

material. The fossils present include barnacles, mollusks, corals, echinoids, foraminifers and 

calcareous nannoplankton. 

 The Tamiami Formation has highly permeable to impermeable lithologies that form a 

complex aquifer. Locally, it is part of the surficial aquifer system. In other areas, it forms a part 

of the intermediate confining unit/aquifer system. 

Tjb - Jackson Bluff Formation - The Jackson Bluff Formation, named by Vernon and 

Puri (1964), occurs at or near the surface in a limited area of the panhandle in Leon, Liberty and 

Wakulla Counties. It has attracted much attention due to its abundant fossil molluscan fauna 

(Huddlestun, 1984; Schmidt, 1984). 

 In the outcrop area, the Jackson Bluff Formation is described as a sandy, clayey shell bed 

(Schmidt, 1984). It is composed of tan to orange-brown to gray green, poorly consolidated, 

fossiliferous, sandy clays to clayey sands. Fossils present include abundant mollusks, corals, 

foraminifers and occasional vertebrate remains. 

Tic - Intracoastal Formation - Limited exposures and shallow subsurface occurrences of 

the Intracoastal Formation have been reported in northwestern Florida (Bay, Franklin, Liberty 

and Wakulla Counties) (Schmidt, 1984). In the subsurface, it occurs to the west across the 

Apalachicola Embayment (Huddlestun, 1984; Schmidt, 1984). 

 The Intracoastal Formation is composed of light gray to olive gray, poorly indurated, 

sandy, clayey, highly fossiliferous limestone (grainstone and packstone). The fossils present 

include foraminifers, mollusks, barnacles, echinoids and ostracods. Quartz sand varies from 

very fine to coarse grained (Huddlestun, 1984). 
OPEN FILE REPORT NO. 80 

20 

Tci - Citronelle Formation - The Citronelle Formation is widespread in the Gulf Coastal 

Plain. The type section for the Citronelle Formation, named by Matson (1916), is near 

Citronelle, Alabama. The Citronelle Formation grades laterally, through a broad facies 

transition, into the Miccosukee Formation of the eastern Florida panhandle. Coe (1979) 

investigated the Citronelle Formation in portions of the western Florida panhandle. The 

Citronelle Formation is a siliciclastic, deltaic deposit that is lithologically similar to, and time 

equivalent with, the Cypresshead Formation and, at least in part, the Long Key Formation 

(Cunningham et al., 1998) of the peninsula. In the western panhandle, some of the sediments 

mapped as Citronelle Formation may be reworked Citronelle. The lithologies are the same and 

there are few fossils present to document a possible younger age. 

 The Citronelle Formation consists of gray to orange, often mottled, unconsolidated to 

poorly consolidated, very fine to very coarse, poorly sorted, clean to clayey sands. It contains 

significant amounts of clay, silt and gravel which may occur as beds and lenses and may vary 

considerably over short distances. Limonite nodules and limonite-cemented beds are common. 

Marine fossils are rare but fossil pollen, plant remains and occasional vertebrates are found. 

 Much of the Citronelle Formation is highly permeable. It forms the Sand and Gravel 

Aquifer of the surficial aquifer system. 

Tmc - Miccosukee Formation - The Miccosukee Formation, named by Hendry and Yon 

(1967), is a siliciclastic unit with a limited distribution in the eastern panhandle. It occurs in the 

Tallahassee Hills from central Gadsden County to eastern Madison County, often capping hills. 

The Miccosukee Formation grades to the west, through a broad facies transition, in central 

Gadsden County into the Citronelle Formation. The Miccosukee Formation is a prodeltaic 

deposit. 

 The Miccosukee Formation is composed of grayish orange to grayish red, mottled, poorly 

to moderately consolidated, interbedded clay, sand and gravel of varying coarseness and 

admixtures (Hendry and Yon, 1967). The unit is relatively impermeable but is considered a part 

of the surficial aquifer system (Southeastern Geological Society, 1986). 

Tc - Cypresshead Formation - The Cypresshead Formation named by Huddlestun (1988), 

is composed of siliciclastics and occurs only in the peninsula and eastern Georgia. It is at or near 

the surface from northern Nassau County southward to Highlands County forming the peninsular 

highlands. It appears that the Cypresshead Formation occurs in the subsurface southward from 

the outcrop region and similar sediments, the Long Key Formation, underlie the Florida Keys. 

The Cypresshead Formation is a shallow marine, near shore deposit equivalent to the Citronelle 

Formation deltaic sediments and the Miccosukee Formation prodeltaic sediments. 

 The Cypresshead Formation consists of reddish brown to reddish orange, unconsolidated 

to poorly consolidated, fine to very coarse grained, clean to clayey sands. Cross bedded sands 

are common within the formation. Discoid quartzite pebbles and mica are often present. Clay 

beds are scattered and not areally extensive. In general, the Cypresshead Formation in exposure 

occurs above 100 feet (30 meters) above mean sea level (msl). 

 Original fossil material is not present in the sediments although poorly preserved molds 

and casts of mollusks and burrow structures are occasionally present. The presence of these 

fossil “ghosts” and trace fossils documents marine influence on deposition of the Cypresshead 

sediments. 
FLORIDA GEOLOGICAL SURVEY 

21 

 The permeable sands of the Cypresshead Formation form part of the surficial aquifer 

system. 

TERTIARY-QUATERNARY SYSTEMS 

TQu - Undifferentiated Tertiary-Quaternary Sediments - These sediments are 

siliciclastics that are separated from undifferentiated Quaternary sediments solely on the basis of 

elevation. Based on the suggestion that the Pleistocene sea levels reached a maximum of 

approximately 100 feet (30 meters) msl (Colquhoun, 1969), these sediments, which occur above 

100 feet (30 meters) msl, are predominantly older than Pleistocene but contain some sediemnts 

reworked during the Pleistocene. This unit may include fluvial and aeolian deposits. The 

undifferentiated Tertiary-Quaternary sediments occur in a band extending from the GeorgiaFlorida state line in Baker and Columbia Counties southward to Alachua County. 

 These sediments are gray to blue green, unconsolidated to poorly consolidated, fine to 

coarse grained, clean to clayey, unfossiliferous sands, sandy clays and clays. Organic debris and 

disseminated organics are present in these sediments. 

 The undifferentiated Tertiary-Quaternary sediments are part of the surficial aquifer 

system. 

TQd - Tertiary-Quaternary Dunes - The dune sediments are fine to medium quartz sand 

with varying amounts of disseminated organic matter. The sands form dunes at elevations 

greater than 100 feet (30 meters) msl. 

TQuc - Undifferentiated reworked Cypresshead Formation - This unit is the result of 

post depositional reworking of the Cypresshead siliciclastics. The sediments are fine to coarse 

quartz sands with scattered quartz gravel and varying percentages of clay matrix. 

Pliocene - Pleistocene Series 

TQsu - Tertiary-Quaternary Fossiliferous Sediments of Southern Florida - Molluskbearing sediments of southern Florida contain some of the most abundant and diverse fossil 

faunas in the world. The origin of these accumulations of fossil mollusks is imprecisely known 

(Allmon, 1992). The shell beds have attracted much attention due to the abundance and 

preservation of the fossils but the biostratigraphy and lithostratigraphy of the units has not been 

well defined (Scott, 1992). Scott and Wingard (1995) discussed the problems associated with 

biostratigraphy and lithostratigraphy of the Plio-Pleistocene in southern Florida. These 

“formations” are biostratigraphic units. 

 The “formations” previously recognized within the latest Tertiary-Quaternary section of 

southern Florida include the latest Pliocene - early Pleistocene Caloosahatchee Formation, the 

early Pleistocene Bermont formation (informal) and the late Pleistocene Fort Thompson 

Formation. This section consists of fossiliferous sands and carbonates. The identification of 

these units is problematic unless the significant molluscan species are recognized. Often 

exposures are not extensive enough to facilitate the collection of representative faunal samples to 

properly discern the biostratigraphic identification of the formation. In an attempt to alleviate 

the inherent problems in the biostratigraphic recognition of lithostratigraphic units, Scott (1992) 
OPEN FILE REPORT NO. 80 

22 

suggested grouping the latest Pliocene through late Pleistocene Caloosahatchee, Bermont and 

Fort Thompson Formations in to a single lithostratigraphic entity, the Okeechobee formation 

(informal). In mapping the shelly sands and carbonates, a generalized grouping as TertiaryQuaternary shell units (TQsu) was utilized. This is equivalent to the informal Okeechobee 

formation. The distribution of the Caloosahatchee and Fort Thompson Formation are shown on 

previous geologic maps by Cooke (1945), Vernon and Puri (1964) and Brooks (1982). 

 The Nashua Formation occurs within the Pliocene - Pleistocene in northern Florida. 

However, it crops out or is near the surface is an area too small to be shown on a map of this 

scale. 

 Lithologically these sediments are complex, varying from unconsolidated, variably 

calcareous and fossiliferous quartz sands to well indurated, sandy, fossiliferous limestones (both 

marine and freshwater). Clayey sands and sandy clays are present. These sediments form part 

of the surficial aquifer system 

Pleistocene Series 

Qa - Anastasia Formation - The Atlantic Coastal Ridge is underlain by the Anastasia 

Formation from St. Johns County southward to Palm Beach County. Excellent exposures occur 

in Flagler County in Washington Oaks State Park, in Martin County at the House of Refuge on 

Hutchinson Island and at Blowing Rocks in Palm Beach County. An impressive exposure of 

Anastasia Formation sediments occurs along Country Club Road in Palm Beach County 

(Lovejoy, 1992). The Anastasia Formation generally is recognized near the coast but extends 

inland as much as 20 miles (32 kilometers) in St. Lucie and Martin Counties. 

 The Anastasia Formation, named by Sellards (1912),is composed of interbedded sands 

and coquinoid limestones. The most recognized facies of the Anastasia sediments is an orangish 

brown, unindurated to moderately indurated, coquina of whole and fragmented mollusk shells in 

a matrix of sand often cemented by sparry calcite. Sands occur as light gray to tan and orangish 

brown, unconsolidated to moderately indurated, unfossiliferous to very fossiliferous beds. The 

Anastasia Formation forms part of the surficial aquifer system. 

Qk - Key Largo Limestone - The Key Largo Limestone, named by Sanford (1909), is 

exposed at the surface in the Florida Keys from Soldier Key on the northeast to Newfound 

Harbor Keys near Big Pine Key on the southwest (Hoffmeister, 1974). This unit is a fossil coral 

reef much like the present day reefs offshore from the Keys. An exceptional exposure of the 

Key Largo Limestone occurs in the Windley Key Quarry State Geological Site in the upper 

Florida Keys. Exposures of the limestone containing large coral heads are in a series of old 

quarries. 

 The Key Largo Limestone is a white to light gray, moderately to well indurated, 

fossiliferous, coralline limestone composed of coral heads encased in a calcarenitic matrix. Little 

to no siliciclastic sediment is found in these sediments. Fossils present include corals, mollusks 

and bryozoans. It is highly porous and permeable and is part of the Biscayne Aquifer of the 

surficial aquifer system 

Qm - Miami Limestone - The Miami Limestone (formerly the Miami Oolite), named by 

Sanford (1909), occurs at or near the surface in southeastern peninsular Florida from Palm Beach 
FLORIDA GEOLOGICAL SURVEY 

23 

County to Dade and Monroe Counties. It forms the Atlantic Coastal Ridge and extends beneath 

the Everglades where it is commonly covered by thin organic and freshwater sediments. The 

Miami Limestone occurs on the mainland and in the southern Florida Keys from Big Pine Key to 

the Marquesas Keys. From Big Pine Key to the mainland, the Miami Limestone is replaced by 

the Key Largo Limestone. To the north, in Palm Beach County, the Miami Limestone grades 

laterally northward into the Anastasia Formation. 

 The Miami Limestone consists of two facies, an oolitic facies and a bryozoan facies 

(Hoffmeister et al. [1967]). The oolitic facies consists of white to orangish gray, poorly to 

moderately indurated, sandy, oolitic limestone (grainstone) with scattered concentrations of 

fossils. The bryozoan facies consists of white to orangish gray, poorly to well indurated, sandy, 

fossiliferous limestone (grainstone and packstone). Beds of quartz sand are also present as 

unindurated sediments and indurated limey sandstones. Fossils present include mollusks, 

bryozoans, and corals. Molds and casts of fossils are common. The highly porous and 

permeable Miami Limestone forms much of the Biscayne Aquifer of the surficical aquifer 

system. 

Qal Qbd Qtr Qu - Undifferentiated Quaternary Sediments - Much of Florida’s surface 

is covered by a varying thickness of undifferentiated sediments consisting of siliciclastics, 

organics and freshwater carbonates. Where these sediments exceed 20 feet (6.1 meters) thick, 

they were mapped as discrete units. In an effort to subdivide the undifferentiated sediments, 

those sediments occurring in flood plains were mapped as alluvial and flood plain deposits (Qal). 

Sediments showing surficial expression of beach ridges and dunes were mapped separately 

(Qbd) as were the sediments composing Trail Ridge (Qtr). Terrace sands were not mapped 

(refer to Healy [1975] for a discussion of the terraces in Florida). The subdivisions of the 

Undifferentiated Quaternary Sediments (Qu) are not lithostratigraphic units but are utilized in 

order to facilitate a better understanding of the State’s geology. 

 The siliciclastics are light gray, tan, brown to black, unconsolidated to poorly 

consolidated, clean to clayey, silty, unfossiliferous, variably organic-bearing sands to blue green 

to olive green, poorly to moderately consolidated, sandy, silty clays. Gravel is occasionally 

present in the panhandle. Organics occur as plant debris, roots, disseminated organic matrix and 

beds of peat. Freshwater carbonates, often referred to as marls in the literature, are scattered 

over much of the State. In southern Florida, freshwater carbonates are nearly ubiquitous in the 

Everglades. These sediments are buff colored to tan, unconsolidated to poorly consolidated, 

fossiliferous carbonate muds. Sand, silt and clay may be present in limited quantities. These 

carbonates often contain organics. The dominant fossils in the freshwater carbonates are 

mollusks. 

Holocene Series 

Qh - Holocene Sediments - The Holocene sediments in Florida occur near the present 

coastline at elevations generally less than 5 feet (1.5 meters). The sediments include quartz 

sands, carbonate sands and muds, and organics. 
OPEN FILE REPORT NO. 80 

24 

REFERENCES 

Allmon, W.D., 1992, Whence southern Florida’s Plio-Pleistocene shell beds: in Scott, T.M., and 

Allmon, W.D., eds., The Plio-Pleistocene stratigraphy and paleontology of southern 

Florida; Florida Geological Survey Special Publication 36, p. 1-20. 

Applin, P. L., and Applin, E. R., 1944, Regional subsurface stratigraphy and structure of Florida and 

southern Georgia: American Association of Petroleum Geologists Bulletin, v. 28, p. 1673-

1753. 

Arthur, J. D., 1988, Petrogenesis of Early Mesozoic tholeiite in the Florida basement and overview 

of Florida basement geology: Florida Geological Survey Report of Investigation 97, 39 

p. 

Braunstein, J., Huddlestun, P., and Biel, R., 1988, Gulf Coast region correlation of stratigraphic units 

of North America: American Association of Petroleum Geologists, Correlation Chart. 

Brewster-Wingard, G.L., Scott, T.M., Edwards, L.E., Weedman, S.D., and Simmons, K.R., 1997, 

Reinterpretation of the peninsular Florida Oligocene: An integrated stratigraphic 

approach: Sedimentary Geology, v. 108, p. 207-228. 

Brooks, H.K., 1982, Geologic Map of Florida: Center for Environmental and Natural Resources, 

University of Florida. 

Bryan, J.R., 1991, Stratigraphic and paleontologic studies of Paleocene and Oligocene carbonate 

facies of the eastern Gulf Coastal Plain: unpublished Ph.D. dissertation, University of 

Tennessee, Knoxville, TN, 324 p. 

Bryan, J.R., 1993, Late Eocene and Early Oligocene carbonate facies and paleoenvironments of 

the eastern Gulf Coastal Plain: Geological Society of America, Southeastern Section 

Meeting, Tallahassee, Florida, field trip guidebook, 25 p.

Cathcart, J.B., 1985, Economic geology of the Land-Pebble Phosphate District of Florida and its 

southern extension: in Cathcart, J.B., and Scott, T.M., eds., Florida Land-Pebble 

Phosphate District: Geological Society of America Annual Meeting, Orlando, Florida, 

field trip guidebook, p. 4-27. 

Coe, C. J., 1979, Geology of Plio-Pleistocene sediments in Escambia and Santa Rosa Counties, 

Florida: unpublished MS thesis, Florida State University, Tallahassee, FL, 115 p. 

Colquhoun, D.J., 1969, Coastal plain terraces in the Carolinas and Georgia, U.S.A.: in Wright, H.E., 

Jr., editor, Quaternary Geology and Climate: Volume 16 of the Proceedings of the VII 

Congress of the International Association for Quaternary Research, v. 16, p. 150-162. 

Cooke, C. W., 1945, Geology of Florida: Florida Geological Survey Bulletin 29, 339 p. 
FLORIDA GEOLOGICAL SURVEY 

25 

Cooke, C. W., and Mansfield, W. C., 1936, Suwanne Limestone of Florida (abstract): Geological 

Society of America Proceedings, 1935, p. 71 – 72. 

Cooke, C. W., and Mossom, S., 1929, Geology of Florida: Florida Geological Survey Twentieth 

Annual Report, p. 29-228, 1 plate. 

Cunningham, K. J., McNeill, D. F., Guertin, L. A., Ciesielski, P. F., Scott, T. M., and de 

Verteuil, L., 1998, New Tertiary stratigraphy for the Florida Keys and southern peninsula 

of Florida: Geological Society of America Bulletin v.110, no. 2, p. 231-258. 

Dall, W.H., and Harris, G.D., 1892, Correlation papers - Neocene: United States Geological 

Survey Bulletin 84, 349 p. 

________and Stanley-Brown, 1894, Cenozoic geology along the Apalachicola River: Geological 

Society of America Bulletin, v. 5, p.147-170. 

Finch, J., 1823, Geological essay on the Tertiary formation in America: American Journal of 

Science, v. 7, p. 31-43. 

Healy, H.G., 1975, Terraces and shorelines of Florida: Florida Bureau of Geology Map Series 

71. 

Hendry, C. W., Jr., and Yon, J. W., Jr., 1967, Stratigraphy of Upper Miocene Miccosukee 

Formation, Jefferson and Leon Counties, Florida: American Association of Petroleum 

Geologists Bulletin, v. 51, pp. 250-256. 

Hoffmeister, J. E., 1974, Land from the sea: University of Miami Press, Coral Gables, FL, 143 p. 

_______________, Stockman, K. W., and Multer, H. G., 1967, Miami Limestone of Florida and its 

Recent Bahamian counterpart: Geological Society of America Bulletin 78, p. 175-190. 

Huddlestun, P. F., 1984, The Neogene stratigraphy of the central Florida panhandle: Unpublished 

Dissertation, Florida State University Department of Geology, Tallahassee, Florida, 

 210 p. 

_________________, 1988, A revision of the lithostratigraphic units of the Coastal Plain of 

Georgia - The Miocene: Georgia Geological Survey Bulletin 104, 162 p. 

_________________, 1993, A revision of the lithostratigraphic units of the Coastal Plain of 

Georgia - The Oligocene: Georgia Geological Survey Bulletin 105, 152 p. 

________________, and Hunter, M. E., 1982, Stratigraphic revision of the Torreya Formation of 

Florida (abstract): in Scott, T. M., and Upchurch, S. B., (eds.), Miocene of the southeastern 
OPEN FILE REPORT NO. 80 

26 

United States, Proceedings of the symposium: Florida Bureau of Geology, Special 

Publication 25, p. 210. 

Lovejoy, D. W., 1992, Classic exposures of the Anastasia Formation in Martin and Palm Beach 

Counties, Florida: Guidebook for combined Southeastern Geological Society and Miami 

Geological Society field trip, 31p. 

Mansfield, W. C., 1939, Notes on the upper Tertiary and Pleistocene mollusks of peninsular Florida: 

Florida Geological Survey Bulletin 18, 75 p. 

Matson, G. C., 1916, The Pliocene Citronelle Formation of the Gulf Coastal Plain: U. S. Geological 

Survey Professional Paper 98-L, p. 167–192. 

________________and Clapp, F. G., 1909, A preliminary report on the geology of Florida: Florida 

Geological Survey Second Annual Report, p. 23-173, 1 plate. 

Matson, G. C., Clapp, F. G. and Sanford, S., 1909, Geologic and topographic map of Florida: in

Matson, G. C., and Clapp, F. G., A preliminary report on the geology of Florida: Florida 

Geological Survey Second Annual Report, p. 23-173, 1 plate. 

Miller, J. A., 1986, Hydrogeologic framework of the Floridan aquifer system in Florida and parts of 

Georgia, Alabama and South Carolina: United States Geological Survey Professional 

Paper 1403-B, 91 p. plus maps. 

Missimer, T.M., 1992, Stratigraphic relationships of sediment facies within the Tamiami 

Formation of southwestern Florida: Proposed intraformational correlations; in Scott, 

T.M., and Allmon, W.D., (eds.), The Plio-Pleistocene stratigraphy and paleontology of 

southern Florida; Florida Geological Survey Special Publication 36, p. 63-92. 

____________, 1997, Late Oligocene to Pliocene evolution of the central portion of the South 

Florida Platform: Mixing of siliciclastic and carbonate sediments: unpublished 

dissertation, University of Miami, Miami, Florida. 

____________ and Scott, T.M., 1995, Late Paleogene and Neogene sea-level history of the 

southern Florida Platform and phosphatic sediment deposition: Congress Program with 

abstracts, v. 1, The First SEPM Congress on Sedimentary Geology, St. Petersburg, 

Florida, August 1995, p. 92. 

North American Commission on Stratigraphic Nomenclature, 1983, North American Stratigraphic 

Code: American Association of Petroleum Geologists Bulletin, v. 67, no. 5, p. 841-875. 

Poag, C. W., 1972, Planktonic foraminifers of the Chickasawhay Formation, United States Gulf 

Coast: Micropaleontology, v. 18, no. 3, p. 267-277. 
FLORIDA GEOLOGICAL SURVEY 

27 

Puri, H.S., 1953, Contribution to the study of the Miocene of the Florida panhandle: Florida 

Geological Survey Bulletin 36, 345 p. 

_______, 1957, Stratigraphy and zonation of the Ocala Group: Florida Geological Survey Bulletin 

38, 248 p. 

________, and Vernon, R. O., 1964, Summary of the geology of Florida:Florida Geological Survey 

Special Publication 5 (Revised), 312 p. 

Sanford, S., 1909, The topography and geology of southern Florida: Florida Geological Survey 

Second Annual Report, p. 175-231. 

Schmidt, W., 1984, Neogene stratigraphy and geologic history of the Apalachicola Embayment, 

Florida: Florida Geological Survey Bulletin 58, 146 p. 

_________, and Clark, M.W., 1980, Geology of Bay County, Florida: 

Florida Bureau of Geology Bulletin 57, 96 p. 

Scott, T. M., 1986, The lithostratigraphic relationships of the Chattahoochee, St. Marks and 

Torreya Formations, eastern Florida Panhandle: Florida Academy of Sciences, Abstract, 

Florida Scientist v. 49, supplement 1, p. 29. 

____________, 1988, The lithostratigraphy of the Hawthorn Group (Miocene) of Florida: Florida 

Geological Survey Bulletin 59, 148 p. 

____________, 1991, A Geological overview of Florida: in Scott, T.M., Lloyd, J. M., and Maddox, 

G. (eds.), Florida's Ground Water Quality Monitoring Program- Hydrogeological 

Framework: Florida Geological Survey Special Publication 32, p. 5-14. 

____________, 1992, Coastal Plains stratigraphy: The dichotomy of biostratigraphy and 

lithostratigraphy - A philosophical approach to an old problem: in Scott, T.M., and 

Allmon, W. D., (eds.) The Plio-Pleistocene stratigraphy and paleontology of southern 

Florida: Florida Geological Survey Special Publication 36, p. 21-26.

____________, in preparation, Geomorphic map of Florida: Florida Geological Survey Map 

Series. 

____________, and Allmon, W. D., 1992, The Plio-Pleistocene stratigraphy and paleontology of 

southern Florida: Florida Geological Survey Special Publication 36, 194 p. 

__________, Wingard, G.L., Weedman, S.D., and Edwards, L.E., 1994, Reinterpretation of the 

peninsular Florida Oligocene: A multidisciplinary view: Abstract, Geological Society of 

America, Annual Meeting, Seattle, WA., Program with Abstracts, p. A-151. 
OPEN FILE REPORT NO. 80 

28 

__________, and Wingard, G.L., 1995, Facies, fossils and time - A discussion of the litho- and 

biostratigraphic problems in the Plio-Pleistocene sediments in southern Florida: in Scott, 

T.M., editor, Stratigraphy and paleontology of the Plio-Pleistocene shell beds, southwest 

Florida: Southeastern Geological Society Guidebook 35, unpaginated. 

Sellards, E. H., 1912, The soils and other surface residual materials of Florida: Florida Geological 

Survey Fourth Annual Report, p. 1-79. 

Sellards, E. H., Gunter, H., and Cooke, C. W., 1922, Geologic map of Florida: in Sellards, E. H., and 

Gunter, H., On the petroleum possibilities of Florida: Florida Geological Survey Fourteenth 

Annual Report, p. 33-135, 1 plate. 

Smith, D.L., 1982, Review of the tectonic history of the Florida basement: Tectonophysics, v. 88, p. 

1-22. 

Smith, E. A., 1881, Geology of Florida: American Journal of Science, 3rd Series, v. XXI, p. 292-

309. 

Southeastern Geological Society (SEGS) Ad Hoc Committee on Florida Hydrostratigraphic Unit 

Definition, 1986, Hydrogeological units of Florida: Florida Geological Survey Special 

Publication 28, 8 p. 

Veatch, O., and Stevenson, L. W., 1911, Geology of the coastal plain of Georgia: Georgia Geologic 

Survey Bulletin 26, 466 p. 

Vernon, R. O., 1951, Surface occurrences of geologic formations in Florida (geologic map): in

Association of American State Geologists Forty-fourth Annual Meeting Field Trip 

Guidebook - A summary of the geology of Florida and a guidebook to the Cenozoic 

exposures of a portion of the State, 116 p., 5 plates. 

Vernon, R.O., and Puri, H.S., 1964, Geologic map of Florida, Florida Bureau of Geology Map 

Series 18. 

Webb, S.D., and Crissinger, D.B., 1983, Stratigraphy and vertebrate paleontology of the central 

and southern Phosphate District of Florida: in Central Florida Phosphate District, 

Geological Society of America, Southeast Section Field Trip Guidebook, p. 28-72. 

White, W. A., 1970, The geomorphology of the Florida peninsula: Florida Bureau of Geology 

Bulletin 51, 164 p. 

Zullo, V.A., Harris, W.B., Scott, T.M., and Portell, R.W., (eds.), 1993, The Neogene of Florida 

and adjacent regions - Proceedings of the Third Bald Head Island Conference on Coastal 

Plains Geology: Florida Geological Survey Special Publication 37, 112 p.